PROJECT SUMMARY Survival has steadily increased in industrialized countries and exceptional longevity beyond 85 years is becoming increasingly common. Who achieves exceptional longevity and why is not well understood, though research has identified some environmental and genetic factors underlying survival to older ages. Greater understanding of prolonged longevity may be gained by considering novel psychosocial determinants. Growing evidence consistently links positive psychological attributes, such as optimism, to more favorable health outcomes, suggesting it may be a powerful health asset. We propose here to study whether and how optimism enhances the likelihood of attaining exceptional longevity (i.e, survival to 85+ years). Given that genetic signatures of exceptional lifespan also predict extended health span, examination of the simpler outcome of exceptional longevity has broad public health significance. We will conduct an in-depth investigation of the underlying mechanisms linking optimism to longevity, considering not only behavioral and biological mechanisms, but also psychological. We will leverage two large epidemiologic cohorts of women (Nurses' Health Studies) and men (Normative Aging Study) with follow-up ranging from 10-50 years. Specific aims are to test a series of hypotheses. First, we will test whether optimism is related to increased likelihood of exceptional longevity in both men and women; we will further examine if these associations are partly explained by behavioral effects of optimism such that higher levels of optimism leads to engaging in healthier behaviors. Second, we will test whether higher optimism is associated with biomarkers that indicate a slower rate of biological aging, considering DNA methylation and telomere length. We will also evaluate if the aging- related biomarkers mediate the relation of optimism to exceptional longevity. Third, we will use daily diary data to evaluate whether optimism is associated with less emotional reactivity in response to daily stressful experiences and more effective emotion regulation; we will explore if these psychological processes mediate the relation of optimism with exceptional longevity. In summary, this proposal will conduct a detailed assessment of mechanisms by which optimism may enhance longevity by leveraging extensive existing data sources, including: repeated measures of optimism, health behaviors, and longevity in two long-running and well-characterized cohorts; biosamples for assaying DNA methylation and telomere length in the women with the same assays already completed in the men; 8-day daily diaries in a subset of men and detailed assessment of emotional regulation in a subset of women. Ultimately, by understanding pathways underlying an association between optimism and longevity, we aim to expand knowledge of possible interventions to promote health in older individuals.